Outdoor Lighting and Crime - Amper

lit more brightly and extensively than are suburbs, and rural areas are dimmer again.
Artificial skyglow diminishes with increasing distance from urban centres. There is an
apparent positive spatial correlation between lighting and crime rate. The population and
crime data sets are again massive. Given the connection between darkness and low crime
mentioned in the preceding section, the spatial evidence suggests that lighting has some
positive causal role in the crime rate, independently of population.
These positive spatial correlations, together with the positive temporal correlations between
lighting and crime rates in historical growth and during power disruptions at night, are
consistent. The occurrence of substantial proportions of crime in daylight is further evidence
against any effective inhibition of crime by brighter lighting, the negative correlation long
assumed and asserted by Situational Crime Prevention practitioners in general.
Experiments claimed to demonstrate a negative effect of lighting on crime typically appear
sufficiently flawed for the evidence to be considered unreliable. Furthermore, the collective
data sets involved in these experiments have relatively limited temporal, spatial and numerical
ranges. In comparison, the data sets used in the present study cover populations from
hundreds to many millions, the crime data are often national totals, and time data range from
less than hours to over a century. The evidence about lighting includes industry literature and
standards, published photometric data for places, general experience of lighting including
airborne views, extensive anecdotal and personal evidence about reduced visibility of celestial
objects, numerous published photographs of skyglow ‘domes’ above cities and towns, and
satellite-derived global maps of upward light emissions. Whatever observational or residual
experimental evidence there is or might be for a non-zero inhibiting effect of lighting on
crime, it appears to be greatly outweighed by the collective evidence for the opposite effect.
9.7 THE LIGHTING, COMMERCE AND CRIME HYPOTHESIS
Interactive causality is hypothesised between outdoor lighting, commerce and crime in
accordance with the balance of available evidence. Increased outdoor ambient light is used
proactively in commerce to attract customers at night. Success increases turnover and profits,
allowing increases in goods, services and facilities in day operations as well as at night. More
people, more goods, more money and extended business hours increase the opportunity and
motivation for crime. This allows lighting to lead indirectly to increased crime. Increased
outdoor ambient light is also used proactively to try to deter crime and reduce fear of crime,
and reactively to try to reduce further crime and fear of crime. Crime can therefore lead to
increased lighting. Crime and commerce likewise interact. Outdoor lighting, commerce and
crime are therefore hypothesised as interacting repetitively in a six-way causal relationship.
The observed net positive correlations indicate the major effect to be lighting indirectly
leading to day and night crime. Any net direct effects would only affect crime at night and
appear to be small.
It seems reasonable to expect that outdoor lighting only allows the crime rate to increase
towards the limiting total value that would be set by the applicable social factors in conditions
where all-night lighting approached daylight levels.
The total amount of outdoor lighting includes that in operation for purposes such as traffic
and mobility safety, advertising, decorative purposes and so on. Lighting installed as a
supposed deterrent or reaction to crime appears to be a minor part of the total and unlikely to
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